KDST tata slack adjusters should not be manually adjusted in an effort to correct excessive push rod stroke. Excessive push rod stroke indicates that a problem exists with the automatic slack adjuster, installation, or with related foundation brake components, which manual adjustment will not fix. Manual adjustment of KDST automatic tata slack adjusters is a dangerous practice that could have serious consequences, because it gives the operator a false sense of security about the effectiveness of brakes which are likely to go out of adjustment again soon.
1. Rotate the hex extension clockwise until the brake linings contact the brake drum. Back off the automatic slack by rotating the hex counter clockwise 1/2 turn.
2. Backing off the slack will require more than 15 ft. lb. of torque. When backing off the slack, a ratcheting sound will be heard.
3. Using a ruler, measure the distance from the face of the air chamber to the center
of the large pin in the clevis (A) (see picture shown below).
4. Make a 90 psi brake application and allow the chamber push rod to travel its maximum
stroke. Measure to the center of the large pin (B). The difference between (A) and (B) is
the push rod stroke. Check the chart on the second page for proper maximum stroke after
adjustment of the brakes.
5. Free stroke is the amount of movement of the slack arm required to move the brake shoes against the drum. With brakes released, measure from the face of the chamber to the center of the clevis pin. Use a lever to measure the movement of the slack adjuster until the
brake shoes contact the drum (See picture below). The difference between the released and applied measurements is the free stroke. The free stroke should be 3/8" - 5/8".
If the free stroke is good, but the applied stroke is too long, there is a problem with the foundation brake. Check the foundation brake for missing or worn components, cracked brake drums, or improper lining to drum contact. If the free stroke is greater than the recommended
distance (3/8" - 5/8"), a function test of the automatic tata slack adjuster should be performed.
If the free stroke is less than 3/8", a dragging brake can occur. Check to see that the manual
adjustment procedure was followed correctly. Manually readjust the brake following the “Brake
Adjustment After Installation” procedure in this pocket guide.
1. Rotate the hex extension clockwise until the brake linings contact the brake drum. Back off the automatic slack by rotating the hex counter clockwise 1/2 turn.
2. Backing off the slack will require more than 15 ft. lb. of torque. When backing off the slack, a ratcheting sound will be heard.
3. Using a ruler, measure the distance from the face of the air chamber to the center
of the large pin in the clevis (A) (see picture shown below).
 |
| Adjusting automatic slack adjuster |
4. Make a 90 psi brake application and allow the chamber push rod to travel its maximum
stroke. Measure to the center of the large pin (B). The difference between (A) and (B) is
the push rod stroke. Check the chart on the second page for proper maximum stroke after
adjustment of the brakes.
5. Free stroke is the amount of movement of the slack arm required to move the brake shoes against the drum. With brakes released, measure from the face of the chamber to the center of the clevis pin. Use a lever to measure the movement of the slack adjuster until the
brake shoes contact the drum (See picture below). The difference between the released and applied measurements is the free stroke. The free stroke should be 3/8" - 5/8".
 |
| Adjusting automatic tata slack adjuster |
If the free stroke is good, but the applied stroke is too long, there is a problem with the foundation brake. Check the foundation brake for missing or worn components, cracked brake drums, or improper lining to drum contact. If the free stroke is greater than the recommended
distance (3/8" - 5/8"), a function test of the automatic tata slack adjuster should be performed.
If the free stroke is less than 3/8", a dragging brake can occur. Check to see that the manual
adjustment procedure was followed correctly. Manually readjust the brake following the “Brake
Adjustment After Installation” procedure in this pocket guide.
